I have Thiel 2.4 & 1.6 in HT. I use rotel 1080 for 1.6 as rear channel but I have hooked it up to drive 2.4. Rotel 1080 (200W per channel into 8ohm, ?W into 4ohm) is enough power for both 2.4 & 1.6. The combo is not bright when fed directly from a Wadia 302. Rotel 1080 is good sound for $600 used. I would not write off the combo.
My 2 channel sys have tube amp driving Avalon and I like warm sound. Rotel with Thiel IMHO not bright. I have owned JM lab Be and B&W signatures which are brighter than Thiel. Thiel is dryer in the midrange than Quad, not brighter.
IMHO, Thiels has a slightly recessed and dry midrange relative to bass and treble. Most people like a little hump at 60-100Hz but treble is exposed by the midrange.
It does not make them bad speakers. All speakers are compromises especially at this price. I own and like Thiel. I have no axe to grind. I would like to share with you the strength and weakness of my speakers. 92 db is sensitive but THiel has low impedance. I am not sure 1070 is OK with 3-4 ohm load. 1080 is more power for not much more dough. THiel image better than Quads. Both are lively and dynamic. I think there are more potential with Thiel. Quad is more balanced. If you like quad, try 21 instead of 22